Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D213/72—Nitrogen atoms
  • C07D213/75—Amino or imino radicals, acylated by carboxylic or carbonic acids, or by sulfur or nitrogen analogues thereof, e.g. carbamates
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D471/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00
  • C07D471/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, at least one ring being a six-membered ring with one nitrogen atom, not provided for by groups C07D451/00 - C07D463/00 in which the condensed system contains two hetero rings
  • C07D471/04—Ortho-condensed systems

Definitions

• This invention relates to a new process for preparing known derivatives of 5,11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepin-6-one, of general formula (I) ##STR6## in which R is H, halogen or CH 3 ;
• R 1 and R 2 are linear or branched chain C 2 -C 4 alkyl groups, which alternatively may be joined together to give a piperazine cycle which can be substituted in position 4 with a CH 3 , C 2 H 5 or benzyl group, and to the salts of said derivatives with organic and inorganic acids.
• German Pat. No. 1,179,943 patented June 10, 1965 describes the preparation of the basic compound of general formula (II) ##STR7## i.e. 5,11-dihydro-6H-pyrido[2,3-b][1,4]-benzodiazepin-6-one; the meaning of R in formula (II) is as defined heretofore.
• compound (VI) is cyclised to give said compound of formula (II), either by direct fusion at 200°-210° C., or in the presence of trichlorobenzene.
• German Pat. No. 1,204,680 patented May 26, 1966 describes the preparation of position 5 derivatives of the compounds of said general formula (II), these derivatives not falling within the scope of the present invention.
• German Auslegeschrift No. 1,795,183 published July 20, 1972 describes a process for synthesizing said compounds of general formula (I) starting from said compounds of general formula (II) prepared by the method of said German Pat. No. 1,179,943, or from their derivatives substituted in position 5.
• these starting compounds (II) are reacted with a halide of general formula (VII)
• Al and Al' which may be equal or different, are chlorine, bromine or iodine.
• the object of the present invention is to prepare said compounds of general formula (I) in such a manner as to obviate the aforesaid problem of the known art, and thus to propose a synthesis which is substantially more economical and has an improved final product yield than the known method.
• a synthesis is proposed which is not of linear type such as that taught by the aforesaid known art, but is of convergent type in that two basic intermediates are obtained by independent paths, each comprising a single passage, the subsequent condensation of the two intermediates giving the final desired product such as to obtain an overall synthesis comprising a substantially small number of passages, thus reducing the loss of the most valuable intermediates formed in the synthesis.
• R 1 and R 2 are linear or branched C 2 -C 4 alkyl groups, which alternatively may be joined together to give a piperazine cycle which can be substituted in position 4 with a methyl, ethyl or benzyl group,
• the reaction of stage (a) is carried out at a temperature chosen between about 160° and 200° C., to give said intermediate of formula (II).
• stage (a) the reaction of stage (a) is carried out at a temperature chosen between about 90° and 130° C., to give a compound of formula (VI) ##STR19## this compound being then converted into said intermediate of formula (II) before proceeding in accordance with said stage (b).
• Said compound of general formula (VI) is converted into the corresponding intermediate of formula (II) by raising the reaction temperature of said stage (a) to about 160° to 200° C.
• said compound of general formula (VI) is isolated from the reaction medium of said stage (a) before proceeding in accordance with said stage (b).
• the reaction according to said stage (b) can be carried out by adding said compound of general formula (XI) to the reaction mixture of said stage (a).
• said intermediate of general formula (II) obtained from said stage (a) is isolated, and then subjected to the reaction of said stage (b) with said compound of general formula (XI) in which R 3 is a halogen.
• a base is used in the reactin of said stage (b), chosen from organic compounds such as triethylamine or pyridine, or inorganic compounds such as sodium carbonate or bicarbonate.
• the present invention also relates to the final compounds of general formula (I) prepared by said process according to the invention, and to said synthesis intermediates of general formula (II) and (VI) obtained during the course of said process.
• the substituted glycine compounds of said general formula (XI) can be prepared from the corresponding amines of general formula (IX) ##STR20## by reaction with monochloracetic acid or an ester thereof, the preparation of which is described for example in the following literature:
• the reaction of said stage (b) can be carried out directly in the same reaction medium as used for preparing the compound of formula (II), without the need to isolate this latter, by adding the glycine derivative of formula (XI) to the reaction mixture of said stage (a).
• the amidation reaction of said stage (b) is carried out by using a glycine derivative of formula (XI) in which R 3 is a halogen, in an inert solvent in the presence of a base in order to fix the hydracid which evolves, at a temperature generally equal to the boiling point of the solvent.
• a base in order to fix the hydracid which evolves, at a temperature generally equal to the boiling point of the solvent.
• This latter can be benzene or toluene
• the base used can be organic, such as triethylamine and pyridine, or inorganic such as sodium carbonate or bicarbonate.
• Heating is commenced, and stirring is started at 60°. Heating is continued until an internal temperature of 100°-120° is reached, and the course of the reaction is followed by thin layer chromatography. This temperature is maintained for 1.5 hours.
• the solution is kept stirred at this temperature for about 1 hour.
• the end of the reaction is determined by thin layer chromatography.
• the temperature of the reaction mixture is then lowered to 90°-100°, and 15.8 g of 4-methyl-1-piperazinacetic acid are incorporated, maintaining this temperature for two hours under stirring.
• the termination of the reaction is determined by the corresponding chromatograph check.
• the solution is poured into 300 cc of water, and neutralised with concentrated ammonia.
• the resultant precipitate is filtered and dried.
• the crude product is dissolved in 250 cc of isopropanol, and 20 cc of hydrochloric isopropanol (28%) are incorporated, to precipitate a product of white cream colour. Recrystallisation from isopropanol gives the dihydrochloride of the product indicated in the title, which has a melting point of 251°-256° (decomposition) (corrected).
• the preparation indicated in example 3 is repeated, and after the cyclising reaction is completed by heating to 170°-190° in polyphosphoric acid, the reaction mixture is cooled to 120°, and is poured under stirring into 2.750 litres of water at ambient temperature. Most of the product then precipitates. The pH is adjusted to 7-7.5, with a 40% sodium hydroxide solution to complete precipitation and change the structure of the precipitate. The mixture must be cooled during neutralisation.
• Heating is commenced, and the mixture is kept at 80° for about three hours.
• the course of the reaction is followed by thin layer chromatography.
• the mixture is cooled to ambient temperature and washed with water (50 cc twice), throwing away the aqueous phase.
• the toluene phase is dried and decolorised with activated carbon. Most of the toluene is removed by distillation under vacuum, isopropanol is added and the mixture distilled azeotropically to eliminate traces of toluene.
• the process according to the present invention consists of a convergent synthesis for the products of general formula (I), i.e. in said stage (a) a first intermediate is prepared (compound of general formula (II)), which, in order to give the final product, is reacted with a second intermediate (glycine compound of general formula (XI)) prepared separately and independently of the synthesis of the intermediate (II).
• the process according to the invention allows the final product (I) to be obtained by a number of passages (at the most three) which is certainly less than the number in the process proposed by the said German patents, thus giving the clear advantage of an economical preparation process.
• the invention therefore advantageously attains the stated objects.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Nitrogen Condensed Heterocyclic Rings (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Pyridine Compounds (AREA)

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Publications (1)

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Cited By (6)

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Citations (8)

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• 1980
  • 1980-03-17 IT IT20700/80A patent/IT1130973B/it active
  • 1980-04-18 FR FR8008809A patent/FR2478099A1/fr not_active Withdrawn
  • 1980-05-13 US US06/149,560 patent/US4308206A/en not_active Expired - Lifetime
  • 1980-06-02 JP JP7283980A patent/JPS56133288A/ja active Pending
• 1981
  • 1981-02-02 ES ES499691A patent/ES499691A0/es active Granted
  • 1981-02-23 AR AR284405A patent/AR226715A1/es active
  • 1981-03-13 DE DE19813109769 patent/DE3109769A1/de not_active Withdrawn

Patent Citations (9)

Non-Patent Citations (1)

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